Antimicrobial multilayer knit fabric having air layer, and manufacturing method therefor

ABSTRACT

The present invention relates to a multilayer knit fabric and a manufacturing method for the same and, more particularly, to an antimicrobial multilayer knit fabric having an air layer and a manufacturing method for the same. The multilayer knit fabric of the present invention comprises an upper knit fabric, a lower knit fabric, and a vertical knit fabric including a monofilament yarn, where the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.

TECHNICAL FIELD

The present invention relates to a multilayer knit fabric and a manufacturing method for the same, and more particularly to an antimicrobial multilayer knit fabric having an air layer and a manufacturing method for the same.

BACKGROUND ART

Disclosed is a three-layer knit fabric, which is knit on a double-sided circular knitting machine in such a way that front and back knit fabrics are bound together with vertical loops.

Korean Patent Publication No. 2002-0060878, filed by Bentex Co., Ltd., discloses a multilayer woven/knit fabric with sweat-absorbent and quick-drying properties that has a three-layered structure consisting of a hydrophobic front tissue layer, a hydrophobic back tissue layer, and a plurality of hydrophilic loops for binding the hydrophobic front and back tissue layers together.

In the conventional knit fabric of such a three-layered structure, however, the loops formed between upper and lower fabrics, that is, vertical monofilament yarns are so weak as to become bent, making the spatial layer insecure so that the resultant fabric has an uneven thickness, and consequently causing some limitations in the use of the final product. As a result, the vertical loops just have a function to bind the front and back fabrics together, and the cross section seen from the outside is made so that it looks as if two single fabrics are joined together.

Korean Patent No. 1566627 presents a double-woven circular knit fabric with high elasticity and its manufacturing method that involves a circular knitting with cotton/ptt/tencel composite Siro-Slub spun yarns used as a surface yarn and sweat-absorbent quick-drying polyester DTY yarns as aback yarn on a 30-36 inch/22-28 gauge double-sided circular knitting machine under the circular knitting conditions of a loop length of 12 to 16 cm and a circular knitting speed of 15 to 20 rpm.

DISCLOSURE OF INVENTION Technical Problem

It is an object of the present invention to provide a novel multilayer knit fabric having upper and lower knit fabrics spaced apart from each other to form an air layer, and a manufacturing method for the same.

It is another object of the present invention to provide a novel multilayer knit fabric with excellent antimicrobial properties that has upper and lower knit fabrics spaced apart from each other to form an air layer, and a manufacturing method for the same.

It is still another object of the present invention to provide a novel multilayer knit fabric with excellent antimicrobial properties and electrical conductivity that has upper and lower knit fabrics spaced apart from each other to form an air layer, and a manufacturing method for the same.

Technical Solution

To achieve the objects of the present invention, the present invention provides a multilayer knit fabric comprising an upper knit fabric; a lower knit fabric; and a vertical knit fabric including a monofilament yarn, wherein the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.

In one aspect, the present invention provides an antimicrobial multilayer knit fabric comprising an upper knit fabric; an antimicrobial lower knit fabric; and a vertical knit fabric including a monofilament yarn, wherein the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.

In another aspect, the present invention provides an electrically conductive and antimicrobial multilayer knit fabric comprising an upper knit fabric; an electrically conductive and antimicrobial lower knit fabric; and a vertical knit fabric including a monofilament yarn, wherein the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.

In the present invention, the upper knit fabric and the lower knit fabric are a relative concept; hence, turning the multilayer knitter fabric over makes the upper knit fabric become the lower knit fabric, and vice versa.

Accordingly, in one aspect, the present invention provides an antimicrobial multilayer knit fabric comprising an antimicrobial and/or electrically conductive upper knit fabric; a lower knit fabric; and a vertical knit fabric including a monofilament yarn, wherein the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.

In the present invention, the upper knit fabric may be a non-antimicrobial knit fabric when the antimicrobial fibers included in the lower knit fabric and/or the vertical knit fabric impart antimicrobial properties to the entire multilayer knit fabric. In embodiments of the present invention, the upper knit fabric may be a non-antimicrobial knit fabric. Yet, the present invention does not limit the upper knit fabric being an antimicrobial knit fabric as necessary.

In the present invention, the upper knit fabric is preferably a yarn dyed fabric in order to avoid dyeing defects of shade variation and unleveled dyeing that possibly occur in the process of piece dyeing.

In the present invention, the type of fibers used in the upper knit fabric may be adjusted as necessary depending on the environments in which the fabric is used.

In embodiments of the present invention, the upper knit fabric may use nylon, polyester, rubber yarn, or a combination thereof. Nylon fiber may be used to provide a soft touch in areas that are in contact with the skin, and polyester fiber may be used to implement a variety of colors in design. Rubber yarn, such as spandex, may be used to provide high elongation and elasticity. Preferably, the upper knit fabric may use fine yarns of 20 D to 50 D.

In the present invention, the lower knit fabric may be a knit fabric containing a copper component. The knit fabric containing a copper component may be a knit fabric resulting from knitting a fiber containing a copper component alone or in combination with another fiber.

In the present invention, the fiber containing a copper component may be a non-conductive fiber. In the present invention, a non-conductive fiber containing a copper component is used to impart antimicrobial properties. The copper component is intermittently adhered to the surface of the fiber, so the fiber acquires antimicrobial properties, but substantially not conductivity, from the copper component. The non-conductive fiber containing a copper component is commercially available, for example, from Kolon Glotech in South Korea.

In the present invention, the fiber containing a copper component may be an electrically conductive fiber. In the present invention, an electrically conductive fiber containing a copper component is used to impart conductivity and microbial properties from the copper component and may consist of a fiber core and a copper component applied on the surface of the fiber core so that it stretches and contracts in concert with the other fiber used in knitting. For example, it may be a conductive fiber having a coating of the copper component on the surface of a nylon fiber. A conductive nylon fiber of which the surface contains a copper component may be manufactured according to Korean Patent No. 1925070, which is incorporated herein by reference in its entirety.

In the present invention, the lower knit fabric may be an interlock knitted fabric resulting from knitting using an electrically conductive fiber containing a copper component and/or a non-conductive fiber containing a copper component in combination with a synthetic fiber such as nylon or spandex.

In the present invention, the lower knit fabric made by interlock knitting may be an interlock knitted fabric resulting from knitting in a striped pattern using an electrically conductive fiber containing a copper component and/or a non-conductive fiber containing a copper component. The interlock knitted fabric may be the known knit fabrics as disclosed in Korean Patent Nos. 1925070, 1925063 and 1866418, which are granted to the applicants of the present invention.

In the present invention, the monofilament yarn of the vertical knit fabric is used to provide strength for supporting the upper and lower knit fabrics to be spaced apart from each other at a predetermined distance.

In the present invention, the monofilament yarn may be a polypropylene monofilament yarn, a nylon monofilament yarn, or a polyester monofilament yarn, and preferably, a nylon monofilament yarn or a polyester monofilament yarn that has a high tensile strength.

In the present invention, the monofilament yarn is preferably a small-diameter monofilament yarn so as to prevent protrusion from the surface of the upper or lower knit fabric during compression due to the rigidity of the monofilament yarn. When the upper and lower knit fabrics contain nylon for a soft touch, the monofilament yarn preferably has a thickness of 20 D to 50 D, more preferably 30 D to 40 D.

In the present invention, in order to prevent the growth of bacteria in the space between the upper and lower knit fabrics formed by the vertical knit fabric, the vertical knit fabric may be made by knitting with a fiber containing a copper component, preferably a non-conductive fiber containing a copper component.

In the present invention, the multilayer knit fabric may have the upper and lower knit fabrics spaced apart from each other by the vertical knit fabric preferably at a distance of at least 0.5 mm, more preferably at least 1.0 mm, still more preferably at least 1.5 mm, and most preferably at least 2 mm.

In the present invention, the distance between the upper and lower knit fabrics means that the fabrics are in a state at which they have undergone a finishing process, such as refining. In a state where the fabrics are greige before refining, the distance is greater by 50% or more.

In the present invention, the multilayer knit fabric may be made by knitting on a conventional double-sided circular knitting machine. In embodiments of the present invention, the double-sided circular knitting machine and the knitting conditions may be appropriately selected depending on the types of the fibers used in the upper and lower knit fabrics and the vertical knit fabric. Preferably, the knitting conditions may include a loop length of 4 to 20 cm, 80 to 150 feeders, and 18 to 30 gauge.

In the present invention, the multilayer knit fabric (greige fabric) knitted on the double-sided circular knitting machine may be subjected to a refining process. In the case where the multilayer knit fabric includes a conductive fiber containing copper, the refining process is preferably conducted in a slightly alkaline environment that is approximately neutral on the pH scale below 8.0, and more preferably 7.5 to 8.0, in order to prevent deterioration of conductivity and antimicrobial properties due to desorption of copper during refining. The refining process may use the methods disclosed in Korean Patent Nos. 1925070, 1925063, and 1866418.

The multilayer knit fabric of the present invention has antimicrobial properties and can be used as products such as a variety of medical clothing, clothing, duvet covers, bed covers, curtains, and masks.

The multilayer knit fabric of the present invention includes an air layer inside to impart a cushion and has electrical conductivity and antimicrobial properties inside, so it may be used as a packaging material or a cover of electronic products, such as a pocket of laptop computers, tablet PCs, or e-readers.

In the present invention, the multilayer knit fabric allows a large amount of water or moisture absorbed into the air layer inside and thus can be used as a water absorbent. In embodiments of the present invention, the multilayer knit fabric can be effectively used for incontinence pads by making use of the inner air layer and the antimicrobial and deodorizing properties of copper.

In embodiments of the present invention, the multilayer knit fabric may further use microfibers or high filament yarns, which are mixed into the upper, lower or vertical knit fabric to increase the water absorption capacity of the multilayer knit fabric.

In embodiments of the present invention, the one side of the multilayer knit fabric may be napped in order to increase the water absorption capacity.

Effects of Invention

The multilayer knit fabric of the present invention includes an air layer between upper and lower knit fabrics to provide cushioning properties, thermal insulation, and moisture or water absorption.

In addition, the multilayer knit fabric of the present invention is able to provide antimicrobial properties that prevent the inner air layer from harboring bacteria. In this case, it is possible to provide a fabric with greater than 99% antimicrobial activity just by using an antimicrobial fabric having poor handfeel properties for the lower and vertical knit fabrics, but not for the upper knit fabric.

In addition, the multilayer knit fabric containing a copper component according to the present invention can provide thin and highly absorbent incontinence pads by making use of the antimicrobial and deodorizing properties of the copper component and moisture or water absorption.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to examples, which are not intended to limit the present invention, but to illustrate the present invention.

EXAMPLES

Preparation of Yarns

Kolon Glotech fiber was used as a non-conductive fiber containing copper. A polyester yarn was 50 denier, and a spandex yarn was a thin yarn of 30 denier.

A conductive nylon fiber containing copper was prepared according to the example of Korean Patent No. 1925070. After a nylon fiber of about 70 denier was added to a reaction tank, the liquor ratio was adjusted to 1:15-20, and 3 to 5 g/L of a deoiling agent was added to treat the nylon fiber for 40 minutes at 60° C. The suspended substances produced by the deoiling agent were removed by application of water. To the reaction tank were added 2-3% o.w.f of levulinic acid, 0.1-0.5% o.w.f of sodium lauryl sulfate, 0.1-0.3% o.w.f of polyethylene glycol, 8-10% o.w.f of sodium thiosulfate, and 0.2% o.w.f of EDTA, 10-20% o.w.f of copper sulfate. After agitation for about 10 minutes, the pH was maintained in the range of 4 to 5 and the temperature was raised to 60° C. at a rate of 1° C./min. The reaction was activated for 60 minutes at 60° C., and 0.3% o.w.f of sodium hypophosphate was added to cause reduction and precipitation for 20 minutes at 60° C. Unreacted substances were removed at the pH of up to 7. 0.3% o.w.f of magnesium hydroxide was added at the pH 7 to treat the nylon fiber for 20 minutes at 40° C. After removal of the residual sulfur, it was confirmed that the resultant conductive nylon fiber had a specific resistance of 10² Ωcm.

Example 1

A double-sided circular knitting machine was provided with feeders for supplying polyester, nylon, and spandex yarns for an upper knit fabric; feeders for supplying a conductive fiber containing a copper component, a non-conductive fiber containing a copper component, a nylon 66 yarn and a spandex yarn for a lower knit fabric; and feeders for supplying a polyester monofilament yarn and a non-conductive fiber containing a copper component for a vertical knit fabric. At the feeders provided for the upper knit fabric, the yarn dyed polyester had a thickness of 75 D, the nylon 50 D, and the spandex 20 D. At the feeders provided for the lower knit fabric, the conductive fiber containing a copper component was 70 D in thickness, the non-conductive fiber containing a copper component 70 D, the nylon yarn 70 D, and the spandex yarn 20 D. At the feeders for the vertical knit fabric, the polyester monofilament yarn had a thickness of 40 D, and the non-conductive fiber containing a copper component 70 D.

The upper knit fabric comprised 15 wt. % of polyester, 10 wt. % of nylon, and 5 wt. % of spandex; the lower knit fabric was composed of 5 wt. % of a conductive fiber containing a copper component, 15 wt. % of a non-conductive fiber containing a copper component, 20 wt. % of nylon, and 5 wt. % of spandex; and the vertical knit fabric comprised 20 wt. % of a monofilament yarn and 5 wt. % of a non-conductive fiber containing a copper component.

The multilayer knit fabric thus manufactured was completed through a refining process, and the upper and lower knit fabrics were spaced about 2 mm apart from each other.

Example 2

The procedures were performed in the same manner as described in Example 1, excepting that the vertical knit fabric used the polyester monofilament yarn alone, not in combination with the non-conductive fiber containing a copper component, while the amount of the polyester monofilament yarn was increased to 25 wt. %.

Example 3

The procedures were performed in the same manner as described in Example 1, excepting that the vertical knit fabric used a nylon 6 monofilament yarn in place of the polyester monofilament yarn.

Example 4

The procedures were performed in the same manner as described in Example 1, excepting that the thickness of the polyester monofilament yarn was changed to 30 D.

Example 5

The procedures were performed in the same manner as described in Example 1, excepting that the lower knit fabric used a non-conductive fiber containing a copper component in place of the conductive fiber containing a copper component.

Comparative Example 1

The procedures were performed in the same manner as described in Example 1, excepting that 25 wt. % of an 80 D cotton yarn was used for the vertical knit fabric.

Comparative Example 2

The procedures were performed in the same manner as described in Example 1, excepting that a 70 D nylon 66 yarn was used for the vertical knit fabric.

Comparative Example 3

The procedures were performed in the same manner as described in Example 1, excepting that a 70 D polyester yarn was used for the vertical knit fabric.

Comparative Example 4

The procedures were performed in the same manner as described in Example 1, excepting that the thickness of the vertical filament yarn was changed to 100 D.

Comparative Example 5

The procedures were performed in the same manner as described in Example 1, excepting that the thickness of the vertical filament yarn was changed to 10 D.

Vertical Strength Test After repeating 500 to 1,000 cycles of 20% fabric compression and recovery on ten spots in a piece of the prepared fabric with an area of 5×5 cm², it was checked whether any dented areas were formed in the surface of the fabric.

TABLE 1 Surface Item 500 cycles 1,000 cycles protrusion Example 1 ◯ ◯ Good Example 2 ◯ ◯ Good Example 3 ◯ ◯ Good Example 4 ◯ ◯ Good Example 5 ◯ ◯ Good Comparative X X Good Example 1 Comparative Δ X Good Example 2 Comparative Δ X Good Example 3 Comparative ◯ ◯ Bad Example 4 Comparative ◯ Δ Good Example 5 ◯: No change in thickness throughout the repeating cycles of 20% fabric compression and recovery. Δ: One or more areas with the thickness reduced by 10% or greater throughout the repeating cycles of 20% fabric compression and recovery. X: Five or more areas with the thickness reduced by 10% or greater throughout the repeating cycles of 20% fabric compression and recovery. Surface protrusion: “Bad” if any minute protrusion was observed in the surface of the upper knit fabric after 500 repeating cycles of 20% fabric compression and recovery; and “Good” if not.

As can be seen from. Table 1, when the vertical knit fabric included a filament yarn having an appropriate thickness, that is, in Examples 1 to 5, resilience after compression was secured to reduce the gap between the upper and lower knit fabrics, thus resulting in no change in thickness.

In contrast, when the vertical knit fabric did not include a filament yarn having an appropriate thickness, that is, in Comparative Examples 1 to 3 using different fibers, Comparative Example 4 having an extremely thick monofilament yarn, and Comparative Example 5 using an extremely thin monofilament yarn, there was a defect involving a reduced gap between the upper and lower knit fabrics or a surface defect in which the vertical knit fabric formed protrusions in the upper knit fabric.

Antimicrobial Test

An antimicrobial test was conducted on the products of Example 1 using an antimicrobial fiber containing a copper component and a polyester monofilament yarn for the vertical knit fabric and Example 2 using a polyester monofilament yarn alone for the vertical knit fabric. The Korean Apparel Testing Institute (www.katri.re.kr, TEL 88-2-561-0844, FAX 88-2-569-6135) located at Dabong Tower 4F, 418 Teheran-Ro, Gangnam-Gu, Seoul was commissioned to perform the antimicrobial test.

In an antimicrobial test for Example 1 using an antimicrobial fiber in the lower and vertical knit fabrics, the prepared fabric was tested for antimicrobial activity according to the KS K 0693:2016. The antimicrobial activity was measured against Escherichia coli (ATCC25922), Staphylococcus Aureus (ATTC 6538), and Klebsiella Pneumoniae (ATTC 4352). The concentration of the inoculum solution was 0.7×10⁵ CFU/mL for each bacterium, and a standard cotton fabric was used as a control. As a surfactant, Tween 80 was added in an amount of 0.05% of the inoculum solution. According to the issued test report (KATAI No: KNAA18-00016180, accepted on Aug. 10, 2018 and issued on Aug. 24, 2018), the test fabric showed an antimicrobial activity of 99.9% against Escherichia coli (ATCC 25922) and over 99.9% against Staphylococcus Aureus (ATTC 6538) and Klebsiella Pneumoniae (ATTC 4352).

In an antimicrobial test for Example 2 using an antimicrobial fiber only in the lower knit fabric, the prepared fabric was tested for antimicrobial activity according to the KS K 0693:2016. The antimicrobial activity was measured against Escherichia coli (ATCC 25922), Staphylococcus Aureus (ATTC 6538), and Klebsiella Pneumoniae (ATTC 4352). The concentration of the inoculum solution was 1.2×10³ CFU/mL for Escherichia coli (ATCC 25922), 1.0×10³ CFU/mL for Staphylococcus Aureus (ATTC 6538), and 0.7×10³ CFU/mL for Klebsiella Pneumoniae (ATTC 4352), and a standard cotton fabric was used as a control. As a surfactant, Tween 80 was added in an amount of 0.05% of the inoculum solution. According to the issued test report (KATAI No: KNAA18-00015377, accepted on Jul. 30, 2018 and issued on Aug. 3, 2018), the test fabric showed an antimicrobial activity of 74.0%, 81.3% and 82.7% against Escherichia coli (ATCC 25922), Staphylococcus Aureus (ATTC 6538) and Klebsiella Pneumoniae (ATTC 4352), respectively. The fabric product using an antimicrobial fiber only in the lower knit fabric had an antimicrobial activity of about 74 to 82%, which was lower than the over 99% antimicrobial activity of Example 1. 

1. A multilayer knit fabric comprising an upper knit fabric; a lower knit fabric; and a vertical knit fabric comprising a monofilament yarn, wherein the upper and lower knit fabrics are spaced apart from each other by the vertical knit fabric to form an air layer inside.
 2. The multilayer knit fabric according to claim 1, wherein the multilayer knit fabric is an antimicrobial knit fabric.
 3. The multilayer knit fabric according to claim 1, wherein the upper knit fabric is a non-antimicrobial knit fabric.
 4. The multilayer knit fabric according to claim 1, wherein the upper knit fabric is a yarn dyed knit fabric.
 5. The multilayer knit fabric according to claim 1, wherein the upper knit fabric comprises at least one fiber selected from the group consisting of polyester, nylon, and spandex, the fiber being a 20-50 D fiber.
 6. The multilayer knit fabric according to claim 1, wherein the lower knit fabric is an antimicrobial knit fabric.
 7. The multilayer knit fabric according to claim 1, wherein the lower knit fabric is an antimicrobial and electrically conductive knit fabric.
 8. The multilayer knit fabric according to claim 1, wherein the lower knit fabric is made by knitting using a fiber containing a copper component and a fiber not containing a copper component.
 9. The multilayer knit fabric according to claim 8, wherein the fiber containing a copper component is a conductive fiber having a coating of the copper component on the surface of a nylon fiber.
 10. The multilayer knit fabric according to claim 1, wherein the monofilament yarn is at least one selected from the group consisting of a polypropylene monofilament yarn, a nylon monofilament yarn, and a polyester monofilament yarn.
 11. The multilayer knit fabric according to claim 10, wherein the monofilament yarn has a thickness of 20-50 D.
 12. The multilayer knit fabric according to claim 10, wherein the monofilament yarn is knitted together with a fiber containing a copper component.
 13. The multilayer knit fabric according to claim 1, wherein the multilayer knit fabric has the upper and lower knit fabrics spaced at least 1.0 mm apart by the vertical knit fabric.
 14. A method for manufacturing the multilayer knit fabric according to claim 1, the method comprising supplying a fiber containing a copper component and a fiber comprising a monofilament yarn to a double-sided circular knitting machine having a 18 to 30 gauge with a loop length of 4 to 20 cm through 80 to 150 feeders.
 15. An antimicrobial or antistatic clothing comprising the multilayer knit fabric according to claim
 1. 16. A water-absorbing fabric comprising the multilayer knit fabric according to claim
 1. 17. An incontinence pad comprising a water-absorbing fabric comprising the multilayer knit fabric according to claim
 1. 